Studies of Corrosion of Aluminium and 6063 Aluminium Alloy in Phosphoric Acid Medium

The corrosion behaviour of aluminium and6063 aluminium alloy was investigated in phosphoric acid of different concentrations at different temperatures. The study was done by electrochemical method, using Tafel polarization and electrochemical impedance spectroscopy (EIS) techniques. The kinetic parameters and thermodynamic parameters were calculated using Arrhenius theory and transition state theory. The surface morphology was studied using scanning electron microscope (SEM) with Energy dispersive X-ray (EDX). The corrosion rate of both the materials increased with increase in the concentration of acid as well as with temperature. The rate of corrosion of 6063 aluminium alloy was found to be higher than that of pure aluminium. Suitable mechanism was proposed for the corrosion of aluminium and 6063 aluminium alloy in phosphoric acid medium. The results obtained by Tafel polarization and electrochemical impedance spectroscopy (EIS) techniques were in good agreement with each other.